ANS webinar explores systematic risk evaluations

The American Nuclear Society's Risk-informed, Performance-based Principles and Policy Committee (RP3C) recently held another presentation in its monthly Community of Practice (CoP) series. Former RP3C chair N. Prasad Kadambi opened the meeting with brief introductory remarks about the RP3C and the value of risk-informed, performance-based (RIPB) techniques in contrast to the shortcomings of conventional, deterministic approaches for the development of nuclear technology.

He then welcomed this month's speaker: William Reckley, a consultant who recently retired after a long career at the Nuclear Regulatory Commission, who presented "A Perspective on Systematic Risk Evaluations."

Watch the full webinar here.

Some background: RP3C is a special committee created by the ANS Standards Board and chaired by Steven Krahn that provides guidance to ANS standards committees on the use of RIPB methods. The CoP is part of RP3C's charter, which includes training and knowledge-sharing of RIPB principles to exchange ideas outside of the normal management and project processes.

Starting off: Reckley opened his presentation by giving some context on the importance of systematic risk evaluations (SREs), saying the topic "has been introduced into some of the recent changes to NRC regulations and related guidance being prepared by both the industry and the NRC." The most familiar type of SRE for the nuclear industry is the probabilistic risk assessment (PRA), but a host of recent changes are raising questions about how other risk evaluation techniques might be used either in combination with or as an alternative to a PRA, he explained.

Before diving deeper into those alternate techniques, Reckley took a step back to review the bigger picture. SREs, he said, are used in risk-informed decision-making related to plant design, licensing, and plant operations.

"These evaluations, the related design choices, and the choices on operational programs can be viewed within the context of risk management," he explained. While many organizations take a stab at defining risk management as a concept, Reckley says each of those definitions are ultimately quite similar.

He cites the Department of Homeland Security Risk Lexicon, which defines risk management as "the process for identifying, analyzing, and communicating risk and accepting, avoiding, transferring, or controlling it to an acceptable level considering associated costs and benefits of any action taken."

Reckley acknowledges that while this broad overview of the big-picture goal is probably not "earth-shattering," it is nonetheless useful for those in the industry to keep their mindset focused on the ultimate aim of controlling the risk associated with the design and deployment of nuclear technologies.

Zooming in: To explain how these overarching concepts and goals play out in regulations, Reckley zoomed in on the requirements of the recently finalized 10 CFR Part 53, "Risk-Informed, Technology-Inclusive Regulatory Framework for Advanced Reactors." Part 53, which Reckley directly worked on during his time at the NRC, is a new, technology-neutral regulatory pathway for the licensing of new reactors, including non-light water designs.

According to Reckley, "We did consciously consider risk management ideas as we were developing Part 53. That was in part because Part 53 is designed to be largely self-contained, and so it had to address the whole cycle of risk management."

Within the risk management process laid out in Part 53, analysis requirements are largely contained in 53.450, which calls for the completion of a PRA, other SREs, or a combination thereof.

While these SREs are left undefined in Part 53, Reckley explained that they need to have more than just a methodical approach to determining what can go wrong in a plant: "The analysis and the evaluations of the risks to establish performance objectives and the need to routinely monitor" are important as well. Reckley also gives special attention to what the term "systematic" means in this context. As he explains, systematic is "not simply the alternative to haphazard," it instead means that the analyses conducted during an SRE act as part of the overall risk management framework.

Go deeper: In his full presentation, Reckley dives deeper into specific examples of SREs that can be used as alternatives to a PRA, the ongoing developments surrounding Part 53, the overlap between NRC licensing and DOE authorization, and much more. The talk is available in full on the American Nuclear Society Standards YouTube channel.